Abstract

Whether global change impacts native and exotic species differently is contentious, as change can favor both native and exotic species over competitors. Plant communities, however, are impacted by multiple global change factors, and whether combined effects of these factors on native-exotic and native-native species interactions are similar is unclear. We tested the hypothesis that the responses of native-exotic and native-native species interactions to multiple global change factors differed in coastal saltmarshes by experimentally manipulating flooding and nutrient enrichment. Together, flooding and nutrient enrichment counteractively effected native-native species interactions but additively effected native-exotic species interactions. This disparity occurred because the exotic species did not have interspecific competition-physical stress tolerance tradeoff that constrained native species. This suggests that multiple environmental changes favor invasive species driven by evolutionary novel life history tradeoff patterns.